1. Field of the Invention
The present invention relates to an image forming apparatus, particularly to a configuration in which a regulating member regulating a position on a sheet width direction is fixed.
2. Description of the Related Art
Conventionally, a copying machine, a printer, and a facsimile can be cited as an example of the image forming apparatus forming an image on a sheet. The copying machine usually includes a function of scanning an original image to form the image on the sheet based on information on the scanned image. Recently some of the copying machines include a communication function to input the image information transmitted from the outside.
The printer forms the image on the sheet based on the image information usually transmitted from an external device such as a computer. The facsimile usually includes the function of scanning the original image and the communication function, the facsimile transmits the scanned image information to the outside, and the facsimile forms the image on the sheet based on the information transmitted from the outside.
In such pieces of image forming apparatus, a sheet feeder apparatus is disposed in a lower portion or a side face of an apparatus main body to feed the sheet from a sheet storage portion in which a large amount of sheets is stacked and stored, and the sheet feeder apparatus feeds the sheet to an image forming portion.
In the sheet feeder apparatus, a sheet feeder unit feeds the sheet from the sheet storage portion, and it is necessary to prevent sheet skew feeding or slip (lateral slip) in a direction orthogonal to a sheet feeding direction when the sheet is fed from the sheet storage portion.
Therefore, a side-end regulating member is provided in the sheet storage portion in order to regulate a position in a sheet width direction. The side-end regulating member can be moved in the width direction according to a size of the sheet accommodated in the sheet feeder apparatus (for example, see Japanese patent laid-Open Publication No. 10-265060).
FIG. 18 illustrates a configuration of a side-end regulating member provided in the conventional sheet storage portion, such as a sheet deck, in which the large amount of sheets is stored. A side-end regulating member 910 includes an abutment portion 910a abutting on a side end of the sheet, a fixing portion 910b extended in a horizontal direction from an upper end of the abutment portion 910a, and an insertion portion 910c extended downward from a lower end of the abutment portion 910a. In FIG. 18, aligning insertion holes 911 are made in a bottom 921 of a sheet storage portion 920 according to the sheet size.
In the case where the sheet having a different size is stored in the sheet storage portion 920, the insertion portion 910c of the side-end regulating member 910 is inserted into a predetermined insertion hole 911 made in the bottom 921 according to the size of the stored sheet. Then, the fixing portion 910b is fixed to the sheet storage portion 920 by a screw 912.
However, in such configurations, the change in position of the side-end regulating member 910 becomes troublesome, and improvement of operability is required. In order to improve the operability, there is proposed a configuration in which a side-end regulating member is provided in the opposite direction to press the side end of the sheet and the side-end regulating members are coupled with a gear and a rack.
In the sheet feeder apparatus including the side-end regulating member having the above-described configuration, after the pair of side-end regulating members is positioned according to the sheet size, it is necessary that the pair of side-end regulating members be locked so as not to be moved.
In an example of the lock unit, when the sheet storage portion is put into the body of the image forming apparatus, a ratchet cog is engaged with the rack gear to prevent slip such that the pair of side-end regulating members is not moved by impact of the weight of the stored sheets. Japanese patent laid-Open Publication No. 9-110193 proposes a technique in which the pair of side-end regulating members is fixed by a frictional force of a frictional member using a force generated in attaching the sheet storage portion to the body of the image forming apparatus.
However, in the conventional sheet feeder apparatus, when the ratchet cog is engaged with the rack gear to prevent the slip, the side-end regulating member can fixed only in each pitch of the rack gear. Therefore, the side-end regulating member slips up to one cog from the position where the side-end regulating member should be locked, which results in the generation of the lateral slip of the sheet.
In the technique in which the side-end regulating members are fixed by the frictional force of the frictional member using the force generated in attaching the sheet storage portion to the body of the image forming apparatus, a load is increased in attaching the sheet storage portion, which deteriorates the operability. When the frictional force is weakened with the operability paramount in thinking, the side-end regulating member slips easily in strongly attaching the sheet storage portion. Additionally, in the frictional member, because the frictional force is decreased by the influence of dirt (paper powder) or time deterioration, the side-end regulating member is hardly stably fixed.